JPS61183382A - Cathode ray tube - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cathode ray tube comprising a luminescent screen comprising luminescent indium orthoborate.

Such a cathode ray tube is disclosed in U.S. Pat. No. 3,394,084.
It is known from the specification of No. This patent discloses a luminescent indium orthoborate (basic lattice ln 803 ) activated by an activator, a lanthanide element, which replaces a portion of the indium in the basic lattice ln 803 . Materials suitable for practical applications include 31i! [There are borates activated by terbium of i that emit green light, and borates activated by trivalent europium that emit red light. In addition, JP-A-Shoyo 60-2299
No. 82 and European Patent Application No. 0111303 disclose activation of In 803 with two activators, both Tb''+ and Eu3+.

These two activated borates exhibit a mixed green and red color, which is very bright even at low active agent contents.

The known decay time of luminescent indium borate is 20Ill
It is about SeC (moderate attenuation). These known borates are suitable for use in data display cathode ray tubes, so-called DGD (data graphics display) tubes, due to their favorable emission color, their strong brightness and their moderate attenuation properties. Particularly suitable for use.

Also, using trivalent chromium as an activator in a given basic lattice, especially aluminate and aluminum oxide,
It is known that chromium can be replaced by An. Such materials generally emit light in the deep red and/or infrared part of the spectrum. Journal "Chemical Abstracts" Volume 97.

In 1982, No. 82135n, for example, chromium-activated YAβ3B+o+z (huntite crystal structure) is described. For certain applications, luminescent materials for cathode ray tubes are useful that emit in the infrared portion of the spectrum.

It is an object of the invention to provide a cathode ray tube provided with a material that fluoresces at least effectively in the infrared part of the spectrum.

The present invention is characterized in that, in a cathode ray tube provided with a luminescent screen comprising luminescent indium orthoborate, the indium orthoborate is activated by trivalent chromium.

Experiments have shown that the indium borate lattice with a calcite-type crystal structure, upon chromium activation, forms a highly effective luminescent material that emits light in the near-infrared spectrum. , has a half width of about 120 rv).

Because the luminescence of transition metals such as chromium is strongly dependent on the crystal structure and composition of the fundamental lattice, it is difficult to expect or predict effective luminescence. This is in contrast to, for example, rare earth metals, which are slightly influenced by the fundamental lattice and can effectively emit light even with large changes in the fundamental lattice.

An advantage of the cathode ray tube of the present invention is that the chromium-activated indium borate does not produce any visible light, or very little. This is important when only infrared light and not visible light is required. Furthermore, the luminescent indium borate has the advantage that it can be obtained in the form of a very fine powder (average particle size, for example, approximately 1 μm). Therefore, the energy efficiency can be as high as that of coarse-grained powders. Fine-grained powders have the advantage that generally less powder matrix is required for the luminescent screen than when coarse-grained powders are used.

In the cathode ray tube of the present invention, the boron'fa salt has the following formula ln I-
P Cr p BO3, where 1.10-5 ≦I)
It is preferable to have a composition represented by ≦5.10-2. With these values of chromium content 1p, high energy efficiencies can indeed be obtained. Furthermore, p is 3.
The highest energy efficiency can be obtained with values in the range 10-4≦p≦1.10-2.

In a preferred embodiment of the cathode ray tube according to the invention, the luminescent screen comprises at least one additional luminescent material. Additional luminescent materials to be used include materials suitable for use in cathode ray tubes for displaying images, e.g. luminescent sulfides such as manganese activated zinc silicate, Ag and CD activated zinc cadmium sulfide, E(I and/or or Tb activated indium borate, and Eu3+ activated oxysulfide.In this way, a data graphic display tube (DGD tube) can be obtained, and this DGD
In the tube, so-called lightbens can be used.

Such Light Ben is an element that selectively responds to infrared rays of Cr-activated indium borate, and using this element,
The position on the image screen can be precisely determined. Computer aided design (CAD)
Alternatively, as used in computer aided manufacturing (CAM), desired information can be added to or removed from areas on the screen selected by Lightben.

In another example of the cathode ray tube of the invention, indium orthoborate is further activated with trivalent europium and has the following formula: 1n 1-P-qCr pEu q B
O3, provided that it has a composition expressed by 3.10-4≦Q≦1.10-1. Therefore, the chromium content p is within the range of 1.10-5≦p≦5.10.
-2 can be selected. Indium borate activated by both chromium and europium emits EIJ3+ bright line emission mainly in the 590-600 nm range while chromium emits light in the infrared region. From now on (Cr and EU
) The energy efficiency of the light-emitting layer was confirmed to be extremely high. The desired spectral distribution of Cr and El emission is adjusted by appropriate selection of Cr and Eu degrees, respectively. Furthermore, it was confirmed that the EU emission in Cr and EU-activated indium borate was extremely efficient, and that an acceptable amount of Cr emission was also maintained.

Therefore, in a cathode ray tube equipped with such indium borate, the image display (at least the display of a red image) and only one
Both an infrared signal and a position determining signal can be obtained from one luminescent material. Furthermore, the efficiency can be improved over that of known borates activated by only Eu in Cr and EIJ-activated boric acids. In these cases, the chromium emission is relatively weak and the cathode ray tube equipped with luminescent boric acid is not suitable for use with known Eu-activated boric acid tubes if only red light is desired and no infrared radiation is desired. This has advantages over conventional cathode ray tubes.

The luminescent indium borate of the present invention can be obtained by using a mixture of oxides of the composition or compounds produced by heating these oxides.
It can also be obtained by solid phase reaction at high temperatures. This solid state reaction is generally carried out in air at a temperature of 1100-1400°C.

Examples of cathode ray tubes according to the invention will now be described in more detail by means of drawings and a number of examples and measurements.

In FIG. 1, 1 indicates the envelope of the cathode ray tube.

The envelope 1 comprises a screen 2 on which a luminescent layer 3 is provided. Luminous screen (2,3)
is provided with chromium-activated luminescent indium orthoborate. The luminescent screen further comprises a luminescent material mixed with chromium-activated indium borate, for example when used in a DGD tube.

Example mixture of preparation: ln 203 0.02 mol, H38
030.08 mol and Cr 20 s 2.10
Xl0-5so! Consists of. This mixture is 100 mol
・Contains % excess H2SO4. This mixture was heated in an oven in air at a temperature of 1200° C. for 8 hours. After cooling, the product was washed with water, then dried, ground and sieved. The resulting powder was a luminescent indium borate according to the formula 1. With cathodoline excitation, this borate has a maximum of 810n+n and a half-width of 12
It emits light in the 0 nm band. The spectral energy distribution of this borate emission is shown in FIG. In FIG. 2, the wavelength λ (nm) is plotted on the horizontal axis, and the radiation energy E for each fixed wavelength interval (in arbitrary units) is plotted on the vertical axis. The energy efficiency of borate was found to be 28% relative to the standard. In this case, green-emitting Cu and A1-activated luminescent zinc cadmium sulfide were used as standards (ρ22. energy efficiency 18%).

In the same manner as described in the Preparation Example above, the formula In I-P
A large number of indium borate of Cr p BO3 was obtained.

Here, chromium-containing ff1p is variable. All of these excited borates are identical to the luminescence of the luminescent material of the preparation example. Table 1 shows the measurement results of energy efficiency η (relative to the same standard).

A number of indium borate 01 activated with both chromium and trivalent europium were prepared by a method similar to the previous preparation example. Desired europium to Eu2
Added as O3 to the firing mixture. In Table 2 below, (
2 shows the measurement results of energy efficiency η (relative to the standard). The multiple vertical rows of Table 2 show the measurement results for materials with a given chromium content 1p and varying europium content q. The six horizontal columns of this table show the measurement results for materials with a given europium content and varying chromium gold deposits. Generally, the energy efficiency of chromium emission (column marked a in the table) and the energy efficiency of europium emission (column marked b in the table) are measured for each substance. The column marked C in the table is the overall efficiency (
Cr and EIJ excitation). This series of experiments contains a small amount of indium borate activated only in europium (see line p-0: these materials are not according to the invention).
Comparing the measured value of the energy efficiency of 1 luminescence (shown in parentheses) with the measured value of the energy efficiency of indium borate according to the present invention, it was confirmed that this energy efficiency is higher for the material of the present invention than for the known material. Ta.

a: Energy efficiency of nichrome emission b: Energy efficiency of europium emission C: Overall energy efficiency 1) Equation in Cr ELI BO3 emission Q, 987 0.008 0.010 The spectral energy distribution of photoborate is shown in Figure 3. Shown in the graph.

803) has an energy efficiency of ELI emission that is 16% higher than the 0.94 0.06 energy efficiency of the known ln Etl 803. The borates of the present invention have half the ELI content of known borates.

[Brief explanation of drawings]

Fig. 1 is a partially cross-sectional side view of the cathode ray tube of the present invention, Fig. 2 is a characteristic diagram showing the spectral energy distribution of luminescence of chromium-activated indium borate, and Fig. 3 is similar to Fig. 2 with chromium and europium activation. FIG. 2 is a characteristic diagram showing the spectral energy distribution of luminescence of indium borate. 1...Envelope 2...Screen 3...
Luminescent layer 11 fist χ (nml FI6.3

Claims (1)

[Scope of Claims] 1. A cathode ray tube provided with a luminescent screen comprising luminescent indium orthoborate, characterized in that the indium orthoborate is activated by trivalent chromium. 2. The borate has the following formula In_1_−_pCr_pB
O_3, but 1.10^-^5≦p≦5.10^-^
2. The cathode ray tube according to claim 1, wherein the cathode ray tube has a composition represented by: 3. The above p is 3.10^-^4≦p≦1.10^-^2
Claim 2 characterized in that
Cathode ray tube as described in section. 4. A cathode ray tube according to any one of claims 1 to 3, characterized in that the luminescent screen comprises at least one additional luminescent material. 5. The indium orthoborate is further activated with trivalent europium and formed into the following formula In_1_-
__p_−_qCr_pEu_qBO_3, however, 3.
The cathode ray tube according to any one of claims 1 to 4, characterized in that the cathode ray tube has a composition expressed by 10^-^4≦q≦1.10^-^1. .